The monitoring or metering of audience media consumption activities, such as the consumption of television and/or radio programs, often involves the encoding of broadcast media at a headend distribution station. Typically, the encoding process encodes or otherwise embeds information such as, for example, ancillary codes identifying respective broadcast sources or stations and/or particular programs, time stamp information, or any other information that may be useful for identifying and analyzing the media consumption activities and/or characteristics of audience members.
The mandate by the Federal Communications Commission that television stations migrate to Advanced Televisions Standards Committee (ATSC) digital television (DTV) service has caused many television network providers to adopt new distribution models that change the characteristics of the network feeds provided to local affiliates for distribution to consumption sites (e.g., consumer homes). For example, in some cases, media content is distributed from the network origination source through the local affiliate(s) and to the consumption sites in a pre-packaged ATSC motion picture experts group version 2 (MPEG-2) DTV format. In other words, the media content is provided in and remains in a compressed digital format throughout the distribution process and is only decompressed and decoded at its final consumption destinations (e.g., consumer homes). The distribution of media content in such a compressed format can significantly reduce transmission costs for high definition program content (e.g., reduces the costs associated with having to purchase satellite bandwidth and the like) and can reduce the capital expenditures (e.g., equipment purchases) by affiliate stations needed to convey high definition program content to consumers. Rather, in these compressed content distribution systems, the local affiliate or final distributor can insert local content (e.g., local programs, commercials, etc.) using an MPEG splicer or the like, which does not require the decompression and/or decoding of the compressed media signal(s) received from the upstream network provider.
The above-noted migration by television stations to distribution models based on the distribution of compressed media content has complicated the task of encoding media signals with metering data (e.g., ancillary codes, timestamps, etc.). For example, some known systems encode media transmitted via a local affiliate with one or more codes identifying that affiliate as a final distributor by encoding an uncompressed version of an audio portion of the media signal with the identifying codes. However, in the case where a local affiliate receives network broadcast media content in a compressed format (e.g., MPEG-2 format), the local affiliate or final distributor cannot easily access the uncompressed audio portion of the compressed media signal(s) received from the upstream network provider. More specifically, in the case of an MPEG-2 compliant media signal, the media signal is provided in a packet-based transport stream or digital data stream that may be carrying multiple programs and, thus, multiple video and/or audio streams. The audio streams are typically composed of compressed audio data (e.g., AC-3 formatted) packets that are interleaved among one another and a variety of other types of packets (e.g., video packets, program association table (PAT) packets, program and system information protocol (PSIP) packets, program map table (PMT) packets, etc.). In any event, the local affiliate or distributor cannot typically easily decompress one or more compressed audio streams, encode those decompressed streams with metering data, and recompress the encoded streams in real-time.